The patent deals with reinforcements used in construction, such as in pillars, beams, supports, girders, etc. The manufacture of reinforcements of this kind is carried out either on site, where the construction is taking place, or in a factory, in which case the prepared reinforcement are transported to the construction site to be arranged in the place in question, that is, for assembly.
A method of carrying out the manufacturer of these reinforcements either on site or in a factory, begins by which a first cutting and shaping operation is carried out on the different pieces of iron needed for the said reinforcement. These pieces of iron are then placed on tables or trestle bents, where a pre-assembly of the reinforcement to be made is carried out. Next, the workers proceed to bind together the meeting points of the pre-assembled reinforcement in the places in question, with the reinforcement being static on the trestle bents and the worker or workers moving along its length until all the necessary points have been bound together, thus giving shape to the reinforcement.
For binding together the meeting points, the traditional way is known, based on manually placing a wire at each point and later braiding it by means of a tool, for instance a pair of pliers or pincers.
This traditional system needs specially skilled workers, called steel erectors or steelworkers, who usually develop a high level of production, in the region of 45 to 50 Kg. of iron per hour and even up to 60 Kg. of iron per hour per person. The problem with this traditional method of assembly lies in the high production costs, due especially to the high cost of skilled labour and its scarcity as workers of this kind are needed by all constructors.
More recently, pre-shaped clips are being used which are fitted where the reinforcement members cross. These clips are provided with projections which are picked up by a tool which automatically braids the said projections until a perfect closure of the clip is obtained.
The advantage of using clips and automatic braiding tools is that highly skilled labour is not needed but that semi-skilled workers and even apprentices can be used. In this case, the production is similar to the previous system, although with the inherent advantage of employment of less skilled workers and the possibility of finding suitable personnel.
The system of welding the pre-assembled reinforcement at the meeting points by using skilled labour is also known. Apart from the kind of welding to be used, with or without flux, the production in Kilograms per hour per person will remain at a maximum of 60 and the welded reinforcement will be more rigid, which is not advisable.
With slight differences, the workers move along the structure in all these methods of carrying out the work, whereas the structure remains static until it is completely bound together and ready for its assembly or transport. Therefore, in all the systems known up to now, these two constants are present: the reinforcements remain static while the workers move. Also in general terms, the production turns out to be limited, as has already been stated, with the maximum amount being some 60 Kg. per hour per person.
More recently, known by means of the French patent 84.14888 of LAFON, is a type of installation based on a flexible machine which has an area for the longitudinal iron parts of the structure to be arranged and another adjacent area for the transverse iron parts, which are stacked up. In this installation, traction on the longitudinal iron parts is carried out amoung the stacked transverse iron parts, taking one transverse iron part each time, which is bound in the traditional way until the structure is completed.
This installation is complex in itself and in the way of proceeding to make up the structure, meaning that its use in practice is not viable given that it is neither cheaper than traditional processes nor increases production.